Refrigeration systems typically include many components, such as compressors, condensers, heat exchangers, and valves which must be connected together in a way that effectively seals the interior of the refrigerant circulation system from the environment around it, as well as provide for the proper flow of fluid through the system. Refrigerants such as Freon which are introduced into such systems as the working fluid are expensive, hazardous to the environment, and sometimes toxic, and it is therefore critical that a closed circulation system be effectively sealed to prevent escape of the fluid or gas.
Further, it is often desirable that a connection between two components of a refrigeration system be easily disconnected, so that installation and replacement of a component may be accomplished without the use of heat connecting methods or extensive tools. To that end, couplings or unions are used to join together components or to couple a component to a line or other conduit.
Typically, these couplings are specialized or custom built for a particular design or manufacturer and cannot be universally used in different systems having different configurations. Furthermore, to perform maintenance activities around such couplings, significant effort is required, as these couplings are often welded, brazed, or otherwise fixed onto the lines, requiring significant effort to remove and replace them.
Certain cooling systems, particularly heat pump units, often include a thermostatic expansion valve (TXV). Such valves regulate the flow of refrigerant between the condenser and evaporator to ensure efficient operation and improved cooling efficiency. Accordingly, many more systems in the future will include a TXV, particularly as new energy requirements (e.g., 13 SEER) require use of a TXV in a cooling system.
Typically, a TXV is coupled between condenser and evaporator via plumbing lines or conduits that are affixed to ports of the TXV, e.g., via a sweat fitting, flare joints or the like. In other systems, a TXV includes a closely coupled nut, i.e., a fixed nut that is permanently attached to the TXV during manufacture, for later use in joining operations in the field. Problems occur in manufacture during attachment of this nut due to overheating caused by welding or other joining operation, causing substantial numbers of manufactured devices to be scrapped. Further as described above, such couplings between TXV and a conduit are typically specialized, raising manufacture costs and further increasing maintenance costs.
A need thus exists for improved couplings, particularly for use in connection with refrigeration and other cooling systems.